Hydraulic jack



June 10, 1930. .1. P. MGBRIDE 1,753,404

HYDRAULIC JACK Filed Nov. 9, 1927 3 Sheets-Sheet l swn Patented Jane 10,1930r UNITED STATES PATENT OFFICE JAMES P- MCIBBIDE,

on NEW YORK, N. Y., ASSIGNOR To MUNKE .Tacx CORPORATION,

OF' NEW YORK, N. Y., A. CORPORATION OF DELAWARE HYDRAULIC JACK .lpplicationled November-9, 1927. Serial No. 232,028.

My invention relates to improvements in hydraulic jacks, and my purpose, generally speaking, is to provide a hydraulic jack, all of the element-s essential to the complete and continued operation of which are embodied in a unitary mechanism which s compact, light and thereforecapable of being transported with facility from one location to another, and which is strong, durable and thoroughly reliable and eiicie'nt, in operation.

More particularlyit is my purpose to pro- Y vide in a 4hydraulic jack, means whereby the liquid used in the operation of the jack is suplied to the pump element thereof'- under sufcient pressure to relieve the pump element of the necessity of any sucking action in its operation. t

My inventive idea is capable of embodiment in different mechanical structures one of which-.is shown in the accompanying drawings. Itis to be understood, however, that V' the structure shown is intended merely as a disclosure of the essential features and novel characteristics of my invention', in one preferred form and that various changes and desirable additions may be made in and to the same within the spirit and scope of my invention as defined in the appended claims.y

In the drawings, wherein like characters of reference denote corresponding parts in the different views Fig. 1 is a central vertical section through a hydraulic jack embodying the features of my invention;

Fig. 2, a lvertical section taken approximately on the line `2--2 of Figure 1;

Fig. 3, a horizontal section on the line 3-3 of Fig. 2; and f Fig. 4, a perspective view of my improved valve.

Referring to the drawings in detail, 10 designates an elongated, hollow cylinder constituting what may be termed the housing of my improved jack, said cylinder including an outer, externally screw-threaded portion 12 and an inner portion 14 which latter, preferably, is of somewhat greater diameter than said outer portion and is equipped with a detachable base 16 forvsu'oporting the jack in 50 upright position.

vthe inner end of the ram member, following An elongated, hollow, cylindrical rammember 18, open at its inner end and closed at its outerv end, is lfitted neatly over the outer portion 12 of cylinder 10 and is adapted for longitudinal sliding movementwith respect thereto, a safety nut 20 being threaded on said outer cylinder portion 12, inwardly of said ram member, to be run outward manually on said portion 12 into engagement with projection of the latter, to prevent accidental 6 collapse thereof with respect to the housing cylinder under the influence of a load on the jack if for any reason the means for projecting the ram member should fail to function properly.'

A relatively long. tube 22 is secured at its outer end to the outer,'closed end ofthe ram member 18 and extends inwardly through a bushing 24 in the outer end of the portion 12 into cylinder 10, terminating, when the ram member is fully retracted with respect to the cylinder 10, as shown in Figure 1 of the drawings, a short distance from the inner end of the inner portion 14 of said cylinder 10.

Within the inner portion 14 of cylinder 10 is a piston 26 carried by the inner end of a rod 28 which extends into the tube 22 and is provided at its outer end with a head 30. A cap 82 is carried by the inner end of tube 22 and between this cap and the head 80 is arranged an expansion coil spring 34 which reacts from said cap through said-rod to maintain a force on the piston 26 tending to move the same outward, whereby liquid 36 which is contained within the cylinder 10 is maintained under slight pressure.

Liquid is adapted to be supplied to the interior of cylinder in any suitable or desired manner, through tube 22 for example, for which purpose the outer end of said tube is provided with a removable plug 38.

Handles 40 are provided on the ram member 18 vfor facilitating handling of the jack.

Secured to the outer end of portion 12 of cylinderlO is an annular cupgasket42 one portion of which seals liquid tight against the inner face of ram member 18 and another portion of which seals liquid tight against the l outer face of tube 22, whereby liquid forced le( under pressure between said vgasket and the outer end of the ram member will not leak into the cylinder 10 past thev tube 22 or to the eX- terior of the jack past the adjacent sliding faces of the ram memberand cylinder 10.

An extension 44 of cylinder 10 projects laterally from the inner ortion 14 of said cylinder and has threaded y engaged therewith a pump cylinder 46 the inner end of which opens into an inwardly tapering valve receiv ing recess 48 formed in said extension. A duct 50 provides communication between the inner end of recess 48 and the interior of cylinder 10 at a point in the latter preferably in the vicinity of the junction of the inner md outer portions 12, 14 thereof, while another duct 52 leads from the recess 48 at a point spaced outwardly from the inner end thereof through theext-ension 44 and the wall of the outer portion 12 of cylinder 10 and hrough the cup gasket 42 to the space between said cup gasket and the outer end of ram member 18. Said duct 52 has arranged therein at any suitable point a check valve 5l opening outward and closing inward with espect to the recess 48.

The outer portion of the bore of pump cylinder 46 is of-slightly smaller diameter than the inner portion thereof, and reciprocal in the outer, smaller bore portion `is a packed piston 56 equipped at its inner end with a cup gasket 58 secured thereto by an extension 60 of said piston which has detachable, screw- -threaded connection therewith.

Extension 60 preferably is of less diameter than the diameter of the inner portion of the bore of the pump cylinder to provide a space around v said extension affording communication be'- tween the outer portion of the pump cylinder, within which piston 56 operates, and the recess 48. Said extension 60 moreover is tubular and open at its inner end and has slidably fitted therein the stem 62 of a tapered valve 64 which is faced with leather or other suitable material and is adapted, to seatnally as best shown in the detail view, Fig. 4,

to provide a pair of resilient tongues 66 adapted frictionally to engage the inner face of tubular extension 60 so thatsaid valve is both movable with and with respect to said extension. v As a consequence of this arrangement when piston 56 and its extension 60 are moved outward valve 64 will be moved outward with the extension 60 away from its seat until its outer end strikes the inner end of pump cylinder 46 or any other suitable abutment, when itsoutivard movement will be arrested while the piston and its extension continue to move outward. In his way valve 64 is moved positively to open position directly by the piston. On the other hand, when piston 56 and its extension 60 are moved inward, valve 64 is moved to its seat during a small initial amount ofsuch inward movement, and being varrested by its seat, continued inward movement ot the piston results merely in the extension 60 sliding over the stem 62, or, in other words, telescoping movement of the stem 62 with respect to the extension 60. Thus it is apparent that the arrangement described 'results also in the valve being moved positively directly by the pump piston to closed position.

The frictional engagement between the stem 62 of the valve and the extension 60 of the pump piston is sufficiently strong to maintain the valve closed against the pressure of the liquid 36 produced by the spring 34 and piston 26 whenever t-he valve is seated, spring ducts 70, 72, respectively, which lead to said recess 68, a manually operable valve 74 of any suitable or preferred type being arranged Within said recess and being movable either' to a closed or an open position, in the former of which it cuts off communication between the ducts 70, 72 and in the latter of which itvpermits vcommunication between said ducts.

Arranged' between the cap 32 and the outer end of the portion 12 of cylinder 10, preferably around the tube 22, is an expansion coil spring 76 which constantly urges the ram member inwardly with respect to the said portion 12, so that when the valve 74 is opened the said ram member will be returned automatically to its normal position shown in Fig. 1 of the drawings.

A laterally and upwardly directed flange i 78 on the pump cylinder 46 provides aseat which rotatably receives the lower end portion of a cylindrical casing 8O in one side of 1 which is journaled a horizontal shaft 82 having fixed thereto anV arm 84 operatively connected with the upper end of piston 56, whereby oscillation of said shaft reciprocates said piston, an actuating handle 86 being connected with said shaft for oscillating same. A ring 88 secured to the flange 7 8 land overlying a lateral flange 90 at the lower end of the casing 8O serves to establish a swivel connection'between the pump cylinder and said casing, while a bolt 92 threaded in said casing with its inner end disposed in an annular groove 94 in the pump cylinder cooperates withsaid swivel connection to prevent outward movement of the casing and also provides means when tightened to lock the easing in any desired rotatably adjusted position with respect to the pum cylinder. When bolt-92 is loosened the casing 80 with los The operation of my improved jack is apparent and as ollowsz-Assuming'the various parts to be in the respective positions shown in the drawings, that is, the ram mem. ber 18 retracted, valvesf64 and 74 closed and the pump piston at its limit of inward movement, the'jack is placed with its base against a suitable abutment and'with the outer end of the ram member against a part to be moved andhandle 86 then is actuated to operate ber should the pump to take liquid from the cylinder 10 and force it between the gasket 42 and the outer end of the ram member to project the latter. Upon outward movement of the piston 56, valve 64 is unseated and the *recessL 48 as well as the portion of the bore of the pump cylinder vvacated by thel piston 56 and its extension 60 becomes filled with liquid flowing throughv duct 50 from the cylinder 10 under `the combined influence of the spring 34 and piston 26 and outward movement of the pump Upon inward'movement of the pump piston, valve 64 is seated and since as a consequence the liquid trapped in the recess 48 and the bore of thev pump cylinder cannot then re- .turn to the cylinder 10, valve 54 is forced open by the pressure on the liquid supplied by the inwardly moving pump piston and the liquid then is caused to flow under pressure through the duct 52 tothe space b'etween the gasket 42 and the outer end of the ram memberwith'the result that it reacts from the outer end of the cylinder 10-to force the ram member outward. Upon repeated operations of the pump piston the ram member obviously is forced step-by-step outward .and asD the ram member is moved outward the safety nut 20 should be threaded outward along the cylinder to form a stop to prevent inward movement of the ram memthe pump mechanism for any rea son fail to function properly. When it is desired to return the parts to normal position all that is necessary` is to thread the nut inwardly on the cylinder 10 and Iopen the valve 74 which permits the liquid to flow from between the gasket 42 and the outer end of the ramy member through the ducts 52, 72, 7 0 and 50 back into the cylinder 10.

It will be noted that since the tube 22 is carried by and moves with the ram member 18, piston 26 will be 4caused to follow up the liquid 36 as it is depleted from the cylinder l0, so that the pressure of spring 34 remains at all times substantially constant.

I claim: 1. In a hydraulic' jack, a hollow housing adapted to contain aliquid, a ram member the suction created by p piston.

carried by and projectible and retractible with respect to said housing, a pump arranged to take liquid rom said vhousing and orce it between the housingand said ram member-to project the latter, and spring actuated means operable to force liquid fromA said housing to said pump.

2. In a hydraulicjack, a hollow housing adapted tocontain a liquid, the housing,` a ram member carried by and projectible and retractible with respect to said housing, a pump arranged to take liquid from said housing and force it between the housing and said ram member to project the latter, and means carried by and movable with said ram member to' force liquid from said housing to said pump.

B. In a hydraulic jack, a hollow housing adapted to contain a liquid, a ram member carried by and -projectible and retractible with respectV to said housing, 'a'pump arranged to take liquid from said housing and force it between the housing and said ram member to project the latter, a piston within lsaid housing' movable 'to force liquid under pressure' fromjsaid housing to said pump, and spring means for so moving said piston.

4. Ina hydraulic jack, a hollow housing adapted to contain a liquid, a ram member carried byand projectible and retractible with 'respect to vsaid housing, a pump arranged to take 'liquid from said housing and force it Vbetween the housing and said ram member to project the latter,'a movable piston within said housing, and a yieldabl'e sup', port 'for 4said piston constantly urging the same ina direction to Jforce liquid from the housing to thepump, a piston within said housing movable to force liquid under pressure from said -housing to said pump, and a yieldable connection between said piston and I cal housing adapted to contain a liquid, a l

hollow cylindrical ram member closed at its outer end and -slidably engaged over said housing, a pump arranged to -take liquid from said housing and force it'between the housing and said ram member to proj eet the latter, a movable piston with said housing,

and ayieldable'connectionbetween said piston and said ram member constantlyv urging the piston in a .direction to force liquid from the housing tothe pump, a piston within said housing,'a yieldable connection between said piston and said ram member, a pump, and means whereby said pump is operable to take liquid from said housing and force it between said abutment and the outer closed end ofsaid ram member.

6. In a hydraulic jack, a hollow cylindri-` cal housing adapted to contain a liquid, a

hollow cylindrical ram member closed at its outer end and 'slidably engaged over said housing, a tube extending inward from the outer endof said ram member into said housing, an abutment on said tube, a, rod within A said tube having 'an abutment thereon,"`an expansion coil spring between the abutment 011 said tube and the abutment on said rod, :,'aid rod extending inwardly beyond the inner end of said tubeand carrying a piston at its inner end slidably engaging said housing,

a pump,and means providing'communication between said pump and vsaid cylinder `:nd between said pump and the space be'- `tween the outer end4 of the housing and the outer end of the ram member.

7. In a hydraulic jack, a housing, a pro*- jectible and retractable ram member mount.- ed on the housing, liquid havin station within the housing on Which the ram mgnber is mounted, and a liftin` station between'the housing and ram mem er, a pump operable to force liquid. to said lifting station to project the ram member, and a piston automatically operable against the liquid at the initial station during actuation of the pump to'exert pressure on said liquid to force the same to the pump.

In testimony whereof I hereunto aix my signature.

JAMES P. lMCBRIDE. f

an initial-l` 

